Boot and shoe



April 17, 1934. H ROLLMNN 1,955,720

BOOT AND sHoE Filed Aug. 9, 193s 2 sheets-sheet 1 5 INVENTOR bym/5 POLL/MAW ATTORNEY April 17, 1934. H. ROLLMANN 1,955,720

BOOT AND SHOE Filed-Aug. 9, 1955-'z 2 Sheets-Sheet 2 b l I M2 l, '1, z

l] l l Il Z Il l' V ll Il INVENTOR ATTORNEY Patented Apr. I7, 1934` UNITED STATES PATENT oFF-lcs Application August 9, '1933, Serial No. A684,295 In Germany March 9, 1932 10 Claims.

This invention relates to improvements in boots and shoes and to the production thereof.- It relates particularly to shoes intended primarily for indoor wear (frequently referred to as slippers or house slippers) but it is applicable to shoes intended for various purposes.

The usual slippers having an upper of fabric, leather, camel hair or other material are generally provided with a soft felt sole. This felt sole may be used directly as the tread or sole proper or else a thin leather sole is secured on the bottom by sewing, by the use of adhesive or the like. Slippers made in this way are extremely hard and inflexible. In addition, felt is comparatively costly as is the leather which may perhaps be used for the tread.

It has been proposed heretofore to make shoes and the like in which there is an intermediate sole formed of sponge rubber, but because of the porous nature of such rubber it has been necessary to provide alateral binding strip or foxing about the edge of the sole and the lower portion of the upper to hold the parts in place and prevent dirt and water from entering the pores of the porous rubber. Furthermore, the lateral strip as well as other elements used in making such shoes have heretofore been cemented together and in place so that it has been necessary to apply the cement and press the strip or parts firmly together. This operation has been performed by hand and is therefore slow and expensive.

A further and important objection to previous practice has been that the porous rubber portion of the sole has had to be madeseparately and formed accurately to size before being joined to other elements of the shoe. It has also been necessary to place the parts in position very carefully before joining the same in order to produce a perfect article.

In accordance with the present invention, these difculties and'objections to the prior art are overcome and an inexpensive and simple method of procedure is provided by which slippers, boots and shoes, etc. having a soft yielding sole of water proof material are formed. In articles embodying the present invention, the felt sole heretofore used as a tread or as an intermediate sole is replaced wholly or in part by a sole of macroporous or micro-porous rubber. If desired, various kinds of rubber can be used for the different pairs of the rubber sole or else rubber can be employed in combination with other materials. The outer sole or tread which in some cases is provided beneath the soft intermediate sole may consist wholly or in part of dense rubber or crepe rubber. Also the slipper may be furnished with a heel piece or wedge consisting of rubber which may be of greater or less density or porosity than that of the remaining portion of thesole. The various parts of such a slipper including the upper may be joined together in any suitable way but are preferably joined by vulcanization.

Preferably the manufacture of the boots and shoes is effected in such a way that the upper which is formed in any desired manner is positioned on a last and placed against a mold corresponding to the shape ofthe sole and containing a lrubber mix which on vulcanization forms a porous or sponge rubber sole.. The last and the' sole mold or their components are subjected to a vulcanizing process after being firmly connected together by screwing or otherwise firmly urging the parts together `in a press or the like, so ,that simultaneously with the forming of the porous sole itself a secure fixing of the sole to the upper is effected. The vulcanizing can be effected in any known manner by means of steam, hot air or the like.

During vulcanization, the rubber mix used in forming the sole expands and lls the mold and due to the pressure developed forces itself into all parts thereof and into pores and interstices in that portion of the material from which the upper is made and which extends into the mold. In this way, a very strong bond between the sole and upper of the shoe is provided. Furthermore, it has been discovered that by vulcanizing the sponge rubber forming mix in situ and within the sole mold, those portions of the rubber mix which come into contact with the mold and which constitute the exposed portions of the flnv-ished sole are formed with a thin and substantially impervious skin which is smooth and free from pores such as are formed in the interior of the rubber. This skin prevents dirt or water from entering the pores of the rubber in the interior of the sole and renders it unnecessary to provide a separate welt or foxing about the edge of the sole or between the edge of the porous rubber sole and the upper. The thickness of the skin extending over the exposed portions of the porous material of the sole may be varied as desired. Preferably, to increase the life of the shoe, a sole of crepe rubber or solid rubber, which latter serves as the tread or actual sole, is inserted in the sole molds. The charge of material for the sponge rubber or the like which becomes porous on vulcanizing is then introduced. During the vulcanizing process the sponge rubber matearticles of this character in which the porous `Vrubber sole is formed with a relatively impervious skin extending over the exposed portions of the sole.

A further object of the invention is to produce and to provide boots, shoes, slippers and the like in which a sole of porous rubber is vulcanized onto an upper.

Another object of the invention is to provide foot wear having a tread of substantially solid rubber, an intermediate sole of porous rubber and an upper, all of which parts are firmly bonded together by vulcanization.

Still another object of the invention is to provide a process in which the sole of a boot, shoe or the like is molded into shape and simultaneously fixed to the upper of the boot or shoe.

A further object of the invention is to provide a process in which a rubber mix containing material for causing the rubber to expand and become porous is placed in a mold adjacent the upper for the shoe and is expanded and fixed to the upper in a single operation.

Another object of the invention is to aflix the sole of a shoe to the upper therefor in a single operation and without the use, of cement for securing the parts together. These and other objects and features of my invention will appear from the following description thereof.

One embodiment of a Islipper according to the invention as wel] as one arrangement for the production of these slippers is shown by way of example in the accompanying drawings in which:

Fig. 1 shows the slipper in partial section,

Fig. 2 s a cross-section through the sole mold and the device for applying pressure.

Fig. 3 is a top view of the sole mold, and

Figs. 4-8 are enlarged cross-sections through various sole molds;

Fig. 9 is a sectional view through a mold and last with the parts of the slipper in place.

The upper a, which may be cut in any desired manner, consists of camelhair or any other suitable material. It may be lined or unlined. The intermediate sole may be of the same constitution throughout its length or may differ at varying points, as is illustrated in Fig. 1 of the drawings, in which the parts b and c are indicated as being made from different materials. Thus for example the parts b and c may be made from sponge rubber of varying degrees of softness.

Beneath the sole is provided a separate outer sole or tread which, however, is not absolutely essential. The tread also may be made of different materials in its various parts d and f, while vthe rear portion (f) of the tread is provided with an attachment or is thickened in a wedge-like manner to form a heel g. The heel may be of porous or dense rubber as required. A sponge rubber insert h may be provided within the slipper and may be fixed or loose.

An advantage which can be attributed to a slipper according to the invention is that, due to the construction of the intermediate sole and the tread, the slipper is appreciably more elastic and is watertight to a greater degree than when the parts of the sole are sewn or cemented together.

In the manufacture of boots and shoes according to the invention (Figs. 2-9), the upper i is formed in known manner and is drawn upon the last lc as shown. Then an adequate quantity of rubber material, which is furnished with an agent for causing the rubber to expand and form sponge rubber, is introduced into mold 1n which can be of any desired shape.

The amount and form of the rubber mix or material for producing the porous rubber sole which is introduced 4into the mold need not be accurately shaped or measured to fill the mold since on vulcanization the material expands considerably and will always fill the mold completely. This result is obtained in every case whether the mold is initially filled completely or not and irrespective of whether the rubber mix has a tendency to expand very greatly or only to a comparatively limited degree. Itis therefore unnecessary to trim or shape the material for the intermediate sole before applying the same or to trim or shape the finished soles after vulcanization. In every case, a product of uniform size and shape is obtained without any finishing operations and without employing skilled labor.

When the parts for forming the sole are assembled, the upper i together with the last k is placed on the mold m and the parts k and m -pressed firmly together by means of a clamp n,

as shown in Fig. 2. Alternatively, any other suitable clamping device can be employed.

As will be apparent from' Fig. 2 of the drawings, the last 1c with the upper in place thereon bears firmly against the upper edge of the mold, so that upon the application of pressure the last and upper are caused to seat accurately upon the mold and the possible escape of the sponge rubber, due to the pressure generated as it swells during the vulcanization process, is prevented.

It is usually desirable to have the last with the insole and upper thereon spaced somewhat from the rubber mix when the parts are assembled and prior to the vulcanization treatment to allow expansion of the porous rubber material during vulcanization. In the construction shown, this is effected by reasonl of the formation of the last and mold, which prevents the last from being forced down onto the rubber mix in such a way that the mix would be displaced and distributed unevenly throughout the mold. Accurate and uniform results are thus obtained in every case,

so that the product is free from variations in thickness of the sponge rubber intermediate sole, which might otherwise occur.

If now the assembled parts are introduced into the vulcanizing furnaceor boiler or if the last is heated internally and if necessary the sole mold heated externally, then simultaneously with the swelling and molding of the rubber contained in the mold m, a rm joining of the sole with the upper i is effected by the vulcanization. so that the sole is formed and in the same operation is simultaneously connected with the upper to form the complete shoe.

The rubber mix which is comparatively plastic I2 when being vulcanized and which is under considerable pressure due to the expansion thereof is forced into all parts and crevices in the mold and into the pores and interstices in and about that portion of the upper and insole or filler 5 which is exposed thereto within the mold. l This insures a very firm bonding of the sole and upper so that no cement, binding strip or foxing. is required to hold the parts together. f l

Normally, the mold for the sole isso chosen U' that it is the required size. However', if desired, the intermediate sole and the sole tread or else the latter alone can be subsequently cut to size. If under the thick flexible -sponge'rubber intermediate sole a tread of crepe or solid rubber is to be provided, then the manufacture of the shoe can be eiected by rst inserting this tread into the mold and then applying the rubber mix for the sponge rubber sole on top of the tread. During the vulcanization, the rubber mix then swells and simultaneously becomes joined with the tread of solid or crepe rubber on the one hand and with the upper on the other hand.

The sole mold may be of varying construction in accordance with the desired shape of the sole. The cross-section of the mold shown in Fig. 4 corresponds to the mold m of Figs. 2 and 3, the lateral edge o of the mold being provided with a flat retaining edge. Ifthe rubber sole is to have an edge projecting beyond the shoe, then the mold can be shaped somewhat as shown in Fig. 5. In this case, the lateral edge o is provided with an inwardly extending projection p. These edges o or p, which abut iirmly against the upper of the shoe when the entire assembly is clamped together, simultaneously serve to prevent the escape of the swelling rubber material in the preparation of the sponge rubber soles. In the mold of Fig. 6, the edge ois cut off obliquely on the outside whereas in Fig. 'l by cutting off the edge o obliquely on the inside, a particularly tight junction between the mold and the upper which is drawn over the last is attained.

In the cross-section of the mold shown in Fig. 8, the inward projection p forming the upper termination of the edge o is provided on its underside with serrations 1', which cause an imitation seam to be impressed on the edge of the rubber sole. Ihe projection p may be any desired size. l

The sole mold shown in Fig. 9 is provided immediately above the base plate s with a widened section t. The sole tread u consisting of crepe rubber, solid rubber or the like can be inserted in this widened portion with the edges v engaged in the recesses t of the lateral edges o of the mold, so that said edges 'u are held between the edges o of the mold and the base-plate s when the clamp n is applied. After the intermediate isole w of porous rubber has been formed in the manner described and the molds have been removed from the shoe, the edges v of the sole tread can `be cut to any desired Width. It is possible to provide slots or recesses in the lower Iedges o of the lateral edges o of the mold which embrace the edges v of the tread u. The molds for the soles may be integral or built up of a number of parts.4 Particularly in the constructions shown in Figs. 5, 8 and 9 which have an inwardly directed projection p at the upper edge, the lateral walls o are preferably formed separately from the base plate.

After vulcanization the mold is withdrawn from the shoe. With the form of mold shown -.in Figs. 2, 3, 4, 6 and 7 the mold is merely moved means of which a pattern is imparted to the apparent that numerous changes and modiflcations may be made in the form and arrangement of the parts employed and the manner of producing boots, shoes, slippers and the like in accordance with my invention without departing from the spirit and scope thereof.

What is claimed is:-

1. A boot, shoe or the like comprising an upper, an intermediate sole of sponge rubber and a tread sole, said intermediate sole being expanded in situ and bonded to both the tread sole and the upper by vulcanization, the lateral edges of said intermediate sole being exposed and formed with an integral non-porous skin.

2. A method of making boots, shoes or the like comprising placing a lasted upper for a shoe against a mold having a cavity of the shape and size of the sole to be formed, said upper forming part of the boundary of said cavity, partly iilling said cavity with an expansible rubber composition, causing said rubber composition to distend into a spongy structure completely i'lliing said cavity and into contact with said mold and said upper, and vulcanizing said rubber compound, whereby a sole of the desired size and shape is formed and is vulcanized to said upper.

3. A process comprising the steps of introducing crepe rubber tread forming material into a mold, introducing a layer of a rubber composition adapted upon vulcanization to undergo expansion and become porous into saidmold and into contact with said crepe rubber, clamping a last having an upper in place thereon into engagement with said mold and subjecting said parts to vulcanization treatment to cause said rubber composition to expand and iill the mold and become vulcanized to both the crepe rubber tread forming material and to said upper.

4. The method of forming a shoe which comprises applying an upper to a last, applying a mold for the lateral portions of the shoe sole to said last, introducing unvulcanized rubber containing an agent for rendering the rubber porous within said mold, applying a layer of relatively dense rubber over said unvulcanized rubber, pressing a cover on saidvmold, xing said last, mold and cover against displacement and. subjecting the assembly to vulcanization treatment.

5. The method of forming a shoe which comprises applying an upper to a last, applying a mold for the lateral portions of the shoe sole to said last, introducing unvulcanized rubber containing an'agent for rendering the rubber porous to said upper and within said mold, applying a layer of relatively dense rubber of greater area than the sole of the shoe to be formed over said unvulcanized rubber, pressing a cover on said mold and in contact with said layer of dense rubber, fixing said last, mold and cover against displacement and subjectingthe assembly .to vulcanization treatment.

6. The method of forming a shoe which comprises applying an upper to a last, placing a mold for an intermediate sole on the upper, introducing' unvulcanized rubber composition which during vulcanization expands and becomes porous, into said mold, placing tread forming material over said composition and vulcanizing said rubber onto said upper and tread forming material under pressure created 'solely by expansion ot tread and a. metal mold.

8. In a method of forming shoes, the steps which comprise placing upon a support which forms part of `a mold a piece of tread forming material larger than the sole to be'formed, placing another part of said mold upon the marginal part of said tread forming material, introducing.

unvulcanized rubber into said mold and into contact with said tread forming material, vulcanizing said rubber onto said tread forming material, and trimming o the excess tread forming material.

9. The method of forming ashoe, which coniprises placing an upper on a last, placing a mold for defining the shape of an intermediate sole in contact with the upper on said last. introducing an unvulcanized rubber composition vcontaining an agent which during vulcanization causes the unvulcanized-rubber to expand and become porous in said mold, placing a piece of tread forming material in position over said unvulcanized rubber so as to extend beyond the margin of said mold, placing a cover over said tread forming material and subjecting said rubber composition to vulcanizing temperature.

10. A boot, shoe or the like comprising an upper, an insole, and a. sole of sponge rubber, said sole being expanded in situ and bonded to the insole and upper by vulcanization, the lateral edges of said sole being exposed and formed with an integral non-porous skin.

HANS ROLLMANN. 

